<?php
//$user = $_POST['user'];
//$pass = $_POST['pass'];

isset($_POST['user'])?$_POST['user']:"";
isset($_POST['pass'])?$_POST['pass']:"";
var_dump(empty($_POST['user']));

$_POST['user']="laozhang";
$_POST['age']="18";

unset($_POST['age']);
var_dump($_POST);

echo PHP_OS;
echo PHP_VERSION;
echo "<hr/>";
define("lgh","罗广华");
echo lgh;